Energy technology最新文献

Metal-organic frameworks (MOFs) often suffer from poor stability, making them suitable precursors for metal oxides/porous carbon catalysts in the oxygen evolution reaction via pyrolysis. High-temperature treatment, however, leads to significant loss of active sites. To address this, Fe-MOFs, FeCo-MOFs, and FeCo-MOFs/graphene oxide (GO) composites using a one-pot hydrothermal method are synthesized and annealed at a low temperature of 300 °C. Characterization reveals that FeCo-MOFs/GO composites possess unique nanowire structures mixed with a small amount of nanoflakes. It is believed that introducing graphene oxide plays a critical role in forming this structure, because the defects in GO provide numerous nucleation sites for nanowire growth. With high specific surface area and good stability, these nanostructures show a low overpotential of 261.5 mV at a current density of 10 mA cm⁻² and a Tafel slope of 20.47 mV dec⁻¹ in 1 mol L⁻¹ KOH alkaline water electrolysis. Density functional theory calculations further indicate that the synergistic effect of Fe and Co atoms enhances the catalytic activity.

The pyrolysis of low alkanes (in the following short “pyrolysis”) has already been investigated during the 1960s. However, none of the reactor systems used at the time are capable of continuous operation. Therefore, the Karlsruhe Institute of Technology has intensified the development of the promising liquid metal bubble column technology in recent years, which is capable of continuous operation. Various key aspects have been addressed, such as scale-up and the pyrolysis of high-caloric natural gas. Herein, further developments for a pilot scale system have been investigated, which concern increased throughput and long-term operation capabilities. Careful evaluation of the impact of according measures has been done, which shows that the achieved scale-up has only negligible effects on the pyrolysis outcome. The effects of the scale-up on residence times are negligible. The bubble formation behavior depends on the throughput and the characteristics of the orifice. Wall effects are marginal. Fundamental minimization of weeping could not be confirmed. Reactor pre-chambers in combination with tin collection chambers are recommended for further scale-up. An increase in the volume flow should be examined. In terms of long-term operation , head as well as feed pressure control is recommended.

Developing an advanced strategy to decrease the charge recombination of BiVO₄ is a vital requirement to boost charge transfer for photoelectrochemical water oxidation. Herein, a type II BiVO₄/Bi₂Mo₂O₉ heterojunction is successfully synthesized on fluorine-doped tin oxide substrate by successive ionic layer adsorption and reaction method. Thanks to the Fermi-level energy difference of 275 mV between BiVO₄ and Bi₂Mo₂O₉, an outward built-in electric filed pointing from Bi₂Mo₂O₉ to BiVO₄ is induced, which accelerates the directional flowing of photogenerated electron and hole. Such a unique design structure fastens the electron migration from BiVO₄ to Bi₂Mo₂O₉, and the holes will transfer to the surface to participate in water oxidation. The longer lifetime (9.2 ns) by time-resolved transient photoluminescence signifies that the Bi₂Mo₂O₉ can boost interfacial carriers’ anisotropic migration; the surface charge transfer rate of BiVO₄/Bi₂Mo₂O₉ is up to 387.6 s⁻¹ (1.4 V vs reversible hydrogen electrode (RHE)). The BiVO₄/Bi₂Mo₂O₉ heterojunction exhibits a remarkable charge separation efficiency of 64% and outstanding photocurrent density of 0.9 mA cm⁻² at 1.23 V versus RHE.

Traditional internal combustion engines (ICEs) have garnered considerable attention due to their high emissions and low efficiency issues. In this study, a novel ICE–fuel cell hybrid power system based on a single-methanol fuel is proposed to address these concerns. The system utilizes methanol as fuel, directly supplying it to the methanol engine, and generates hydrogen for the fuel cell through methanol reforming technology. The structural design of the system fully exploits engine exhaust, first using waste heat for methanol reforming to produce hydrogen and then utilizing exhaust inertial potential energy to drive a dual turbocharging structure for air compression entering the fuel cell, thereby achieving self-thermal balance. Thermodynamic analysis and cost evaluation indicate that the thermal efficiency of this system is improved by 8.34% compared to traditional diesel engine setups. Compared to engine-fuel cell hybrid systems that do not utilize waste heat, the thermal efficiency is increased by 5.81%. In terms of economics, the cost of the methanol engine system is ≈.1466$ $��{�\text{kW\hspace{0.17em}h}�}^{�-�1�}�$, which is 44.05% lower than the 0.262 $$��{�\hspace{0.17em}�\text{kW\hspace{0.17em}h}�}^{�-�1�}�$ fuel cost of traditional diesel engine systems. This study presents an innovative solution that significantly enhances thermal efficiency and offers economic advantages, providing a viable approach to address the low efficiency and high emissions issues of traditional ICEs.

Fe-group nanoalloys are one of the most promising next-generation anodes for lithium-ion batteries (LIBs) due to their low cost, high capacity, excellent electrical conductivity, and lithium-storage capability. However, the difficulties in constructing nanostructures and the tendency for alloy nanoparticles to agglomerate limit their practical application. Herein, a hybrid embedding structure with microporosity–mesoporosity is constructed by using thin-walled carbon nanotubes (CNT) as the support. Within this structure, ultrasmall FeNi/CoNi alloy nanoparticles (10 nm) are uniformly embedded into the walls of thin-walled CNTs (FNNT/CNNT). Benefit from this hybrid structure is that the agglomeration of FNNT/CNNT is effectively suppressed, leading to excellent cycling stability and high capacity (596.6 mA h g⁻¹ for FNNT and 557.1 mA h g⁻¹ for CNNT after 300 cycles at 1 A g⁻¹) as anodes for LIBs. In the present method, a reference can be provided for the preparation of metal alloy/carbon nanocomposites.

Cs₂AgBiBr₆ is a promising lead-free double perovskite solar cells (PSCs) material. Its full potential has yet to be realized due to issues with its large band gap and the optimization of the alignment of the electron transport layer (ETL) and hole transport layer (HTL). The photovoltaic performance of Cs₂AgBiBr₆-based devices has been optimized using ZnO, IGZO, TiO₂, WS₂, PCBM, and C₆₀ ETLs and Cu₂O, CuScN, CuSbS₂, NiO, P3HT, PEDOT: PSS, Spiro MeOTAD, CuI, CuO, V₂O₅, CBTS, and CFTS HTLs. It has been observed by simulation study that Cs₂AgBiBr₆-based devices exhibit remarkably high photoconversion efficiency when combined with certain ETLs. To better understand the performance, we examine how the best device structures are affected by the absorber and ETL thickness, ETL carrier density, series and shunt resistance, generation, and recombination rate. The findings suggest that TiO₂ and ZnO ETLs, in conjunction with CBTS HTL, exhibit good potential for producing high-efficiency (η > 13%) Cs₂AgBiBr₆-based heterojunction solar cells with an ITO/ETL/Cs₂AgBiBr₆/CBTS/Au device structure. Optimization of the valence band offset (VBO) at the CBTS/Cs₂AgBiBr₆ interface reveals that reduced VBO value has a beneficial impact on the performance of the solar cell. This modeling work gives a prospective route for manufacturing lead-free Cs₂AgBiBr₆ PSCs.

A hybrid approach is proposed for optimizing distribution systems (DSs) by integrating clean energy sources, specifically photovoltaic (PV) and wind power (WT). The proposed technique combines the mud ring algorithm (MRA) and quantum neural network (QNN), referred to as the MRA-QNN technique. The primary objective is to minimize power loss and enhance voltage stability. The MRA method generates the control signal of the converter, while the QNN method predicts the control signal based on the MRA output. The effectiveness of the approach is revealed through simulations on standard IEEE 33 bus and 69 bus systems. Implementation in MATLAB shows superior performance compared to existing methods, with lower power loss values. There has been a sustained rise in the system voltage profile (In the WT and PV situations, 0.950. and 93 p.u), as well as a considerable reduction in the active power (AP) losses (to 132.39 kW with PV and 81.23 kW with WT from 362.86 kW). With PV, the entire yearly economic loss is lowered from $158932.68 to just $57996.939, and with WT, it is decreased to $56805.479. With three PVs, the yearly economic loss and active power losses are decreased to 30419.871 $ and 69.449, and 4.27 kW and 1875.930 $, respectively.

Aqueous zinc-ion batteries (AZIB) are increasingly recognized as a promising next-generation energy storage technology, prized for their affordability and high safety profile. Yet, their widespread adoption is challenged by complex reaction mechanisms and the evolving nature of both the electrode material and interfaces, which remain critical barriers. This review underscores the utility of in situ and operando characterization techniques in AZIB systems, offering invaluable tools for tracking these intricate processes and deepening understanding of energy storage mechanisms. This review presents an extensive overview of cutting-edge in situ and operando methods, emphasizing their crucial role in structural investigations of materials and interfaces during electrochemical processes. This review particularly focuses on the synergistic application of various in situ techniques, delving into the nuances of experimental setups and data interpretation. Finally, it addresses current challenges in the field and proposes potential strategies, aiming to enhance the impact and broaden the application of these techniques for future advancements and mechanistic insights in AZIB research.

The performance of lithium–sulfur (Li–S) rechargeable batteries is strongly dependent on the entrapment of the higher-order intermediate polysulfides at the sulfur cathode. An attracting way of preventing the polysulfide shuttle is by introducing a polar host which can form a Lewis acid–base complex with polysulfides. Herein, the Li–S battery by incorporating iron sulfides (FeS₂) as a polar Lewis acid to entrap higher-order polysulfides at the cathode center is investigated. FeS₂/S cathode demonstrates largely improved retention of capacity compared to C/S cathode (capacity fading per cycle of 0.12% and 0.80% for FeS₂/S and C/S respectively) and good rate performance in Li–S batteries compared to conventional carbon–sulfur (C/S) cathode. This is attributed to the decrease in polysulfide dissolution and better retention of active sulfur in the cathode during battery cycling which is due to the polar FeS₂ additive that well anchors polysulfides. The effect of FeS₂ in preventing the shuttle mechanism is demonstrated by ex situ UV–vis spectroscopy and ex situ Raman spectroscopy studies.